1. Field of the Invention
The present invention relates to a picking apparatus of a module IC (Integrated Circuit) handler used for automatically handling and testing module ICs. More particularly, the invention relates to a gripper for such a picking apparatus.
2. Description of the Conventional Art
Typically, a module IC refers to a substrate where one side or both sides of the substrate are used for mounting a plurality of ICs and/or electrical components, for example, by soldering. Typically, memory ICs are mounted on the substrate, and the module IC has a function for extending a memory capacity of a computer when the module IC is coupled to another substrate, such as a mother board of the computer.
A module IC usually provides higher added-value when sold, as compared with the sale of the individual ICs. For this reason, the IC manufacturers tend to develop it as a main product and sell it.
However, the typical module IC is relatively expensive, and thus requires high reliability to ensure customer satisfaction. This requires strict quality tests, wherein only products determined to be good pass. Module ICs that do not pass the tests are discarded.
The testing of module ICs usually begins when the module ICs are contained in a customer tray 101, as shown in FIG. 1. The module ICs 103 can be safely maintained in the customer tray 101, wherein the customer tray 101, includes a box-type body 105 having a plurality of partition walls 104. However, each insertion slot 102 provided inside of the customer tray 101 has a greater width than the width of the module ICs 103 themselves, as shown in FIGS. 1 and 2. This allows the module ICs 103 to be inserted into and removed from the slots 102 without damaging the module ICs 103.
Also, usually a manufacturer uses only one kind of customer tray 101 to accommodate various kinds of module ICs 103, each of whose widths may be different. This requires that the customer tray 101 have slots 102 wide enough to accommodate the largest of the module ICs. As a result, the slots 102 may be much wider than the most narrow of the module ICs.
In order to reduce costs the customer tray 101 is usually vacuum molded, rather than injection molded. Vacuum molding often results in relatively bad precision in the formation of the insertion slots 102.
As a result of all the above facts, when module ICs 103 to be tested are accommodated in the customer tray 101, the module ICs 103 are placed in the insertion slots 102 with arbitrarily different inclinations of the ICs 103, as shown in FIG. 2. Due to the distinct configuration of the customer tray 101, the distances between the inserted module ICs are different from each other, respectively.
When the module ICs are to be tested in an automated testing machine, the module ICs must be removed from the customer tray with automated grippers. Usually, a plurality of grippers are mounted on a movable arm of the testing machine so that the arm can grasp a plurality module ICs simultaneously.
A xe2x80x9cpicking apparatusxe2x80x9d 110 having a plurality of gripping devices 108 is shown in FIG. 4. The picking apparatus is designed so that a spacing between the grippers matches the spacing between the module ICs in a customer tray. As shown in FIG. 5, the gripper 108 includes jaws 109, one or both of which may be movable so that the gripper can pick up modules ICs by their end edges.
Because the spacing between the grippers 108 of an automated test machine is fixed, when the machine is used to automatically test module ICs, the module ICs must be provided in trays that hold the module ICs at a precise spacing corresponding to the spacing between the grippers, like the one shown in FIG. 3. If the module ICs were held in a customer tray like the one shown in FIG. 2, the grippers would have problems effectively grasping the module ICs due to the irregular spacing between the module ICs.
Also, known types of grippers have jaws 109 made of metal, or other hard materials. The jaws of known grippers 109 can damage the module ICs due to an impact between end edges of a module IC 103 and the jaws 109. This problem is made worse when the module ICs in a customer tray are not properly aligned with the gripper jaws, as can occur when module ICs are loaded into a customer tray as shown in FIG. 2. Further, if the IC is not properly aligned when it is grasped by the jaws of a gripper, additional feeding problems can occur with the gripper tries to place the module IC in a test socket or a carrier.
Moreover, known gripper devices often do not maintain a regular grasping tension, due to lack of damping means, which also causes gripping and feeding errors.
It is an object of the present invention to provide a gripper for a picking apparatus of a module IC test handler that is capable of picking up module ICs without damaging the module ICs.
It is another object of the present invention to provide an improved gripper for a picking apparatus which is capable of grasping and moving module ICs that have been tilted at angles.
In order to accomplish the above objects, a gripper embodying the invention includes: a gripper body; a first support, a second support and a third support, all of which are vertically formed at a lower part of the gripper body; a cylinder for driving at least one jaw located between first and second supports and the second and third supports; a pair of jaws movably connected at a lower part of the cylinder and configured to grasp a module IC; damping means for reducing an impact when a module IC is gripped by the jaws; and a module IC sensor for sensing the presence of a module IC.